Silicon nitride optical phased array for compact light-sheet fluorescence microscopy

Abstract

We experimentally demonstrate a silicon nitride photonic integrated circuit beam former for light-sheet fluorescence microscopy operating at a central wavelength of 525 nm. The device integrates 256 grating emitters arranged along two symmetric 90-degree arcs with a radius of curvature of 0.5 mm. The photonic integrated circuit is positioned at the back focal plane of a plano-convex illumination lens, forming a structured, Bessel-like light sheet at the imaging focal plane. The light sheet exhibits a lateral width of 22.9 μm, an axial thickness of 5.15 μm, and a non-diffracting propagation length of 7.5 mm. Tuning the wavelength within 520-530 nm enables lateral steering of ±148 μm without mechanical movement, while thermally actuated phase dithering between the two sides of the optical phased array smooths the beam envelope and homogenizes the field intensity. This work demonstrates a compact and alignment-free approach to wavelength-steered light-sheet generation and transitions from free-space to integrated, chip-scale high-resolution microscopy setups.

Authors 3

1. Alireza Tabatabaei Mashayekh Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen Univ. (Germany)

2. Yuntian Ding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen Univ. (Germany)

3. Jeremy Witzens Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen Univ. (Germany)